Pete Conkle sections off new pasture for his cattle.

When do I start grazing?

By Victor Shelton, retired NRCS Agronomist/Grazing Specialist

Certainly, if you have any stockpiled forage left from the previous season, that is game for grazing. To have decent quality at this time, it had to be good stockpile from last fall with adequate nitrogen present and is likely tall fescue which holds its value better over winter than other grasses.

During this time of year, you absolutely want to make sure that you have enough residual forage present to not only provide fodder for the livestock, but also protect the soil surface. That generally means a minimum of at least 3,000 pounds of dry matter or a good thick ten inches of forage. If you don’t have good cover and the soil is thawed and wet, you can quickly do more damage than good. Even if you have good cover, you shouldn’t let your livestock stay on any one place too long. They have got to keep moving or they will damage the sod opening it up to pesty weeds, erosion and yield reducing compaction.

Pastures that were grazed to the nubbins last fall are going to require more rest and will be slower to respond in the spring. Fields that are continuously grazed close lack deep roots and structure and are more subject to damage under wet conditions and also slower to respond in the spring.

Pastures that were stockpiled and grazed after going dormant are in a little better shape and, depending on how fast regrowth comes, can usually be grazed sooner than others. Stockpiled pastures that had adequate residue left behind, usually a minimum of 3 to 4 inches, are really good places to start grazing and are actually better balanced as far as crude protein, nitrogen, carbon and fiber are concerned. These will grow quicker in the spring because of better root reserves and will often have slightly warmer soils beneath them. Perennial plants are alive year around and just appear dormant above the soil surface. Below ground, there is always some biological and microbial activity going on.

So, here is how to answer the real question of the day — “when do I start grazing? Preferably, you will want to start grazing when the plants are at least 8 to 10 inches tall (tall cool-season forages such as fescues and orchardgrass) and the ground is dry enough to support the weight of the livestock without causing damage to the forage base. That is slightly taller than I used to recommend. Sufficient growth that includes enough fiber, is, or should be, the goal.

Immature forage is very high in crude protein (nitrogen) and low in fiber. All ruminant livestock need to balance the carbon nitrogen ratio in their rumen to maintain that mat. If they don’t then they will not perform the way we want them to, i.e., less gain, less milk production. It goes through them faster than they can effectively utilize it. Immature forage that lacks sufficient fiber can also lower the rumen pH. Rumen pH drops as feed is digested rapidly and rises when the rate of digestion slows. Acidosis occurs when acid is produced faster than it can be used. Those pastures with no residual left from the previous season and are extremely lush new growth are the greatest risk. It’s all about the fiber!

Now, this can be avoided by a smooth transition from fed forages to pasture by making sure the forages have enough growth prior to grazing or the addition/supplementation of some hay with the lush pasture. That will help to advocate for the ruminant livestock, but it will still have a negative impact on the total production of the field for the year. Just like a grazing event during the growing season, the forage plant needs to be able to fully express itself and that takes patience with both us and the livestock. The forage plant early in the spring is pulling reserves from the roots and starting photosynthesis. Being consumed at this time slows the process and reduces resilience and long-term growth potential for the season.

A crop field with leftover corn residue and a winter annual planted in it can help provide some early grazing without concern of damaging pastures but are best grazed while frozen or dry to help deter compaction. Fall-planted spring oats may look a bit anemic in the early spring if there are any left but mixed with new growth from something like cereal rye, the combination makes pretty good grazing. Immature annuals without enough fiber present can have similar issues as short lush early pasture.

I was recently told about a conversation between a guy and his wife as they traveled down a highway. She noticed cows grazing on a hilltop and said, “That is so pretty.” The husband agreed, but also noted that there really wasn’t much left to graze. The producer probably thinks he is saving some hay, but it comes at a cost of grass this coming summer. Time to shut the gates and wait until the grass is really ready to graze!

Enough of that topic for now. It is not too late to do some frost-seeding or overseeding of clover. The successfulness now is the seeds’ ability to reach the soil and start growing before it gets too much competition from existing perennial plants. Fertilizer is high and seed is also no bargain. Clover seed is higher than normal and probably won’t get any better until new supplies from this year are bagged. That said, even with higher price tags, the addition of more clover this year could be a game changer. Adding clover to pastures and hayfields where it is lacking can increase forage production and improve forage quality because of high digestibility and protein and help boost the grass component of the stand.

Legumes can utilize atmospheric nitrogen. Biological nitrogen fixation occurs on legume root nodules due to a special symbiotic relationship the plant has with bacteria. That is why it’s important to inoculate the seed. Most legumes have a very specific rhizobium needed to fix nitrogen so to get the biggest bang for your buck, make sure it’s present.

Clover can produce an incredible amount of nitrogen for the sward if the correct rhizobium is present. Nitrogen this year is about one dollar per pound. If the clover can provide even 100 pounds of nitrogen to the stand, then that clover is worth at least $100 per acre for the nitrogen. Clover can sometimes provide a lot more than just 100 pounds. I usually recommend that the legume be 30-40 percent of the stand by dry weight. Bloat causing legumes, which do include red and white clovers, should never be over 50 percent of the stand.

I’ve said this before, but I’ll say it again, shop and choose a high-quality seed, named varieties and from reputable companies. Do the math and seed at pure live seed (PLS) rates. Take the amount of seed needed (4 lbs. per Acre PLS) and divide it by (percent purity x percent germination). Four pounds divided by (.95 x .80) = 5.26 pounds of seed needed per acre. You can do the same calculation and compare prices by dividing the price of the seed per pound by the PLS percent and see what the true cost is of the seed. Three dollars and twenty cents per pound seed at the previous PLS rate is actually about $4.21 per pound ($3.20/(.95 x .80)) due to the lower germination. Compare that price of the “bargain” seed, always checking the seed tag and testing date. A bargain is not always a bargain.

Remember, it’s not about maximizing a grazing event, but maximizing a grazing season! Keep on grazing!

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